William h



NOV. 14, 1939. w H, SHIFFLER ET AL Re. 21,265

PROCESS FOR PRODUCING ALUMINUM CHLORIDE Original Filed May 23, 1928Reissued Nov. 14, 1939 UNITED STATES PATENT OFFICE PROCESS FOR PRODUCINGALUMINUM HLORIDE tion of Delaware Original No. 1,887,566, dated November15, 1932, Serial No. 279,949, May 23, 1928. Application for reissueMarch 20, 1937, Serial No. 132,183

6 Claims.

This invention relates to the production of aluminum chloride or othermetallic halide by heating carbonaceous material containing aluminumcompounds or other metallic compounds in contact with chlorine gas andin the presence of oxygen.

For purposes of illustration, the process of our invention will bedescribed as relating to the production of aluminum chloride, althoughit may be also used in the manufacture of other metallic halides.Aluminum chloride is generally manufactured by contacting a mechanicalmixture of alumina and carbon at high temperatures with chlorine.Naturally occurring ores, such as bauxite, may be used as the source ofalumina and powdered coal or coke or asphalt may supply the carbon forthe reaction.

A method and apparatus for producing metallic chlorides from finelydivided mixtures of carbonaceous material and metallic compounds hasbeen invented by John Kuhl and William H. Shiffier and is disclosed in acopending application for patent. The present invention relates to asimilar process but is primarily directed to the treatment of cokedmixtures of alumina and carbon in comparatively large lumps anddiscloses a means for producing aluminum chloride (or other metallichalide) more efficiently and economically than other methods and devicesin current use. The efficiency and economy of the process is due largelyto continuous operation and to the fact that dilute chlorine gases, suchas are produced from the Well known Deacon process which provides aconcentration generally too low for eflicient chlorination, may beemployed.

An object of this invention is to disclose a continuous process for theproduction of aluminum chloride from an alumina-containing coke.

Another object of the invention is to disclose a continuous process ofchlorinating alumina-carbon mixtures with dilute chlorine gases in thepresence of heat,

Another object is to provide a process of treating coke in the form ofgranules or lumps in counter-current flow to heated gases comprisingmixtures of air and chlorine to produce aluminum chloride in suitableform for use as a treating agent for mineral oils.

A still further object of this invention is to provide a method ofchlorinating alumina-carbon mixtures in an eiiicient and economicalmanner.

Other objects, results and advantages of our process will becomeapparent from the following detailed description thereof. Forillustrative purposes, one preferred form of apparatus for carrying outthis invention is also shown and the advantages resulting from theparticular character and arrangement of elements and the apparatus willalso become apparent from the subsequent description.

The appended drawing referred to hereinafter E illustrates one form ofapparatus diagrammatically, the invention not lying in specific detailsof construction, but in the general arrangement and combination ofelements, the details of con- L struction being within the skill of theengineering and mechanical arts.

The raw material upon which the process or method of this invention maybe carried out, may

be any coke or carbonaceous material containing ing what is termed a"coke containing alumina,

which is a macroscopically homogeneous intimate mixture of carbon andalumina.

It has been discovered that any alumina-coke of the above describedcharacter may be efiiciently and economically chlorinated and treatedfor the recovery of valuable products by passing the coke through aretort counter-current to the flow of highly heated gases containingchlorine.

For example, the coke containing alumina may f be charged into the topof a vertical retort and a bed of coke made within the retort whilehighly heated gases (such as air or air and producer gas) containingchlorine are introduced at the bottom of the retort so that aluminumchloride is produced during the passage of the gases through the mass.

Aluminum chloride thus produced is in the form of vapor, and as such iscarried from the top of the retort to suitable recovery means, while thespent coke or ash is withdrawn from the bottom either intermittently orcontinuously The vaporized aluminum chloride together with other gasesof the reaction may be scrubbed with oil to condense and absorb thealuminum chloride in the form of a suspension or tar which is suitablefor use as a treating agent for mineral oil. The use of oil incondensing and absorbing aluminum chloride is particularly efiicaciousin the treatment of the dilute product resulting from the process ofthis invention.

The method provides for the contact of partially reacted and preheatedmixture of carbon and alumina (coke containing alumina) with chlorineand air at relatively high temperatures of the latter, thereby allowingthe chlorinating reaction to take place progressively and insures asubstantially complete conversion of all alumina present in the cokeinto aluminum chloride.

A novel means of continuously maintaining the required temperature ofreaction is also provided, so that none of the carbon in the aluminacoke will be utilized in generating the heat, if this saving of carbonin said coke is desired.

The invention hereinbefore described may be more fully understood byreference to the attached drawing which, as has been stated before,illustrates one form of apparatus which may be used in carrying out thebroad aspects of our invention.

In the drawing, I represents a vertical, internally heated retort ofsuitable height and size and lined interiorly with a suitable refractorymaterial. The retort I is provided with a feeding device 2 forintroducing alumina coke of any desired description into the retort.

The feeding device 2 may be provided with double doors 3 and 4 so thatcoke may be charged into the retort intermittently or it may be fedcontinuously by a suitable continuous feeder during the reaction takingplace within the retort I, without the escape of vapors therefromthrough such coke feeding means.

Highly heated gases are introduced into the lower portion of the retortI and they may be heated by means of a separate carbon monoxide gasproducer 5 which is charged with a suitable coke such as a fuel coke oflow volatile matter content through a feeding device 6 which may also beprovided with double doors I and B. The gas producer may also beprovided with double clean out doors such as the doors or valved outlets9 and III, thereby allowing the removal of ashes intermittently orcontinuously without the escape of vapors. The gas producer 5 is furtherprovided with an inlet II near the bottom of said producer 5 forchlorine gas and air which are discharged from the producer through anoutlet I2, leading into the lower portion of the vertical retort I.

The highly heated gases containing chlorine pass through the bed of thecoke containing alumina within the retort I and a reaction takes place,resulting in the formation of aluminum chloride in the form of a vapor.Spent coke and ashes resulting from this reaction may be discharged fromthe vertical retort I through double outlet or discharge means I3 andI4.

It will be seen that the coke present in the upper portion of the retortI is preheated by the gases and vapors generated in the lower portion ofthe retort and the highly heated gases introduced into the retort Ithrough the inlet l2 first come in contact with the preheated andpartially reacted coke. It will be understood that any other means ofheating gases such as air and chlorine may be used and the invention isnot to be limited to the generation of heat by a combustion of the cokein a separate gas producer. As a matter of fact, some air may beintroduced together with the chlorine and carbon monoxide and othergases into the retort I and the portion of heat of reaction derived froma partial combustion of coke within the retort I.

The desirability of generating heat by partial combustion of coke withinthe retort I depends somewhat upon the character of the coke being fedto the retort and the proportional quantity of carbon in the coke. Forexample, if the alumina coke does not contain a large excess of carbon,then it may be desirable to preheat the gases entering the retort in agas producer as shown.

The aluminum chloride, together with other gases, leaves the retort Ithrough a vapor outlet I5 in the upper portion of the retort I and thesemixed gases are then conducted to a downtake pipe IS in which they arebrought in contact with a spray of cooling and absorbing oil admittedinto the upper portion of the downtake pipe I6 by line I1. This coolingoil serves to condense and wash down a portion of the aluminum chloridepresent in the gases discharged from the retort I through pipe means I5and such oil, together with absorbed or condensed aluminum chloride, isdischarged into an oil and tar settling chamber I8. By tar is meant athick rather viscous suspension which is formed by the absorption ofaluminum chloride in an oil.

Gases or components not condensed or absorbed by cooling oil in thedown-take pipe I6 then pass from the upper portion of the settlingchamber I8 upwardly through a scrubbing tower 1 I9 which may be a packedtower as shown in which a large surface area of contact between thegases and a cooling or absorbing medium is provided. The cooling orabsorbing medium may be introduced into the upper portion of the towerI9 through line 20 and discharged into the tower by any suitable spraynozzles or the like. Gases or components not absorbed or condensedwithin the tower I9 then pass out of the system by line 2| to storage orother treating apparatus, as desired, condensed and absorbed productsbeing carried downward into settling chamber I8. Since large volumes ofgases containing but a small quantity of aluminum chloride aredischarged by the retort, condensation of aluminum chloride on cooledsurfaces is impractical since heat transfer is ineffective butabsorption of aluminum chloride by means of oils as stated hereinaboveis very effective since it produces essentially perfect contact betweenthe gases and the absorbing oil, the gases may be passed in large volumeand at high velocity, and this method obviates the use of an interveningsolid wall through which heat transfer must take place.

The lower portion of the settling chamber In is provided with an outletpipe 22 which leads to a pump 23 so that oil containing aluminumchloride may be withdrawn from the lower portion of the settling chamberI8 either intermittently or continuously as desired to storage or foruse as a treating agent for mineral oils by various well known aluminumchloride processes, by line 24.

Cooling oil may be introduced into the system by means of line 25provided with a valve 26. Valves 2'! and 28 are provided so as toregulate the amount of cooling oil being introduced into the down-takepipe I5 and scrubbing tower I9,

respectively. Cooling oil containing substantially 3| may then bereturned by line 32 to line H and to the down-take pipe and scrubbingtower.

Excess oil accumulating in the system may be removed therefrom bydischarging the oil from the upper portion of the settling chamber l8 bymeans of line 29 and pump 30 into an outlet line 33, valve 35 beingclosed and valve 35 in line 33 being open.

The advantages of the above described method and apparatus wll beevident to those skilled in the art. Although a method and apparatushave been described with particular reference to an embodiment shown inthe drawing, it is to be understood that invention is not limitedthereto, but numerous changes and modifications may be made within thescope of the following claims.

We claim:

1. The method of chlorinating coke containing alumina to producealuminum chloride, comprising: carbonizing a mixture of alumina and afluid pitchy substance whereby a macroscopically homogeneous cokecomprising an intimate mixture of carbon and alumina is formed; forminga bed of such coke containing alumina in a vertical retort; maintainingthe said bed in the retort by introducing such coke into the upperportion of the retort and discharging ash and spent coke from the bottomportion of the retort; continuously introducing into the bottom of theretort a dilute chlorine gas mixture including air, the proportion ofair in the mixture being suflicient to maintain a reaction temperaturewithin said bed but containing a ratio of oxygen to nitrogen no higherthan that which exists in air; continuously discharging gases andvaporized products of reaction from the upper portion of the retort; andcontinuously removing condensible products including aluminum chloridefrom the discharged gases by contact with oil.

2. The method of chlcrinating coke contain ing alumina comprising,forming a macroscopically homogeneous coke containing alumina by mixingalumina and a pitchy substance and carboniaing the mixture, forming andmaintaining a bed of said coke in a vertical retort, introducing saidcoke containing alumina into the upper portion of said retort, forming amixture of gases containing chlorine by continuously passing air andchlorine through a separate bed of coke, heating said gases to areaction temperature by combustion of coke in said separate bed,introducing the heated dilute chlorine gas mixture including air intothe lower portion of the vertical retort, said heated gas mixturecontaining oxygen in no higher proportion than that which exists in air,passing the heated gases upwardly through the bed of coke containingalumina in said retort, and discharging gases and vaporized products ofreaction from said retort.

3. A method of chlorinating coke containing alumina to produce aluminumchloride, com prising carbonizing a mixture of alumina and a fluidpitchy substance whereby a macroscopically homogeneous coke comprisingan intimate mixture of carbon and alumina is formed; forming a bed ofsuch macroscopically homogeneous coke containing alumina in a verticalretort introducing such coke containing alumina into the top of saidretort, discharging spent coke and ash from the bottom of said retort,passing a dilute mixture of chlorine and air through a separate retortcontaining coke, heating the dilute chlorine gas mixture by combustionof coke within said separate retort, discharging heated gases containingchlorine and air from said separate retort into the lower portion of thevertical retort, the proportion of air in the mixture being suiiicicntto maintain a reaction temperature within said bed but containing aratio of oxygen to nitrogen no higher than that which exists in air,passing the heated gases upwardly through the bed of coke containingalumina in said retort, and discharging gases and vaporized products olreaction from said retort.

i. A method of chlorinating coke containing alunilina comprising,forming a bed of macroscopically homogeneous coke containing aluminaderived by carbonizing a mixture of alumina and asphalt in a verticalretort, introducing such colic containing alumina into the top of saidretort, discharging spent coke from the bottom or said retort, passing adilute chlorine gas mixture including air into the lower portion of thevertical retort and upwardly through the bed of coke containing aluminain said retort, said gas mixture passed into the retort containingoxygen in no higher proportion than that which exists in air anddischarging gases and vaporized products of reaction from said retort,and continuously condensing aluminum chloride from the dilute gasesdischarged from the retort by contact with oil.

5. A method of chlorinating coke containing alumina to produce aluminumchloride comprising, iorming a bed of macroscopically homogeneous cokecontaining alumina derived by carbonizing a mixture of alumina andasphalt in a vertical retort, intioduoing such coke containing aluminainto the top oi said retort, discharging spent coke from the bottom ofsaid retort, passing a dilute chlorine gas mixture including air intothe lower portion of the vertical retort and upwardly through the bed ofcoke containng alumina in said retort, said gas mixture passed into theretort containing oxygen in no higher proportion than that which existsin air, discharging gases and vaporized products of reaction from saidretort, and continuously condensing condensible products from the dilutegases discharged from said retort by contact with oil.

6. A method of chlorinating coke containing alumina to produce aluminumchloride, comprising introducing a macroscopically homogeneous cokederived by carbonizing a mixture of alumina and asphalt and comprisingan in timate mixture of carbon and alumina into a reaction chamber,maintaining a bed of said coke in said reaction chamber, continuouslyintroducing into the bottom of the chamber dilute chlorine gas mixtureincluding air, the proportion of air in the mixture being sufiicient tomaintain reaction temperature in said reaction chamber but containingoxygen in no higher proportion than that which exists in air, passingsaid gases through the bed of coke in said chamber, continuouslydischarging gases and vaporized products of reaction from the upperportion of said chamber, discharging ash and spent coke from the bottomportion of said chamber, and continuously removing condensible aluminumchloride from the gases and vaporized products of reaction by contactwith oil.

WILLIAM H. SHIFFLER. WARD P. ANDERSON.

CERTIFICATE OF CORRECTION.

Iovember 11 1959 WILLIAM H. SHIFFLER, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 5,second column, line 27, claim 11, after the word "from" insert the upperportion of; and that the said Letters Patent should be read with thiscorrection Reissue To. 21 ,265.

therein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this 50th day of January, A. D. 19b0- Henry VanArsdaie,

(Seal) Acting Commissioner of Patents.

